Import 3D model from CityEngine into Blender and edit UV Map
To UV Unwrap your model, Go to Edit mode of your object and select all the mesh, then press U on your keyboard to open UV Mapping options and select smart UV project, 



after change your window mode to UV mapping,



and finally open the texture you want to give to your object in the bottom bar, 



once you opened you can scale and move your UV map untill it matches your texture how you want it.To scale press S key, to move press G key